struct student
{
  char name[15];
  int roll;
  student*next;
};
 
void display(student*first)
{
  student*ptr;
  ptr=first;
  cout<<"\nCurrent List:\n";
  while(ptr!=NULL)
  {
    cout<<"NAME: "<<ptr->name<<"\nROLL: "<<ptr->roll<<"\n\n";
    ptr=ptr->next;
  }
}
 
void delet(student*first, int val)
{
  student*ptr,*list;
  ptr=first;
  while(ptr!=NULL)
  {
    if(ptr->roll==val)
    {
      list=ptr;
      ptr=ptr->next;
      delete list;
    }
  }
}
 
 
void main()
{
  student*first, *last, *x;
  first=last=NULL;
  int c=0, val, choice, n, i;
  char ch='y';
 
  while (c==0)
  {
    clrscr();
    **menu**
    cout<<"\n\nEnter Your Choice: ";
    cin>>choice;
 
    switch (choice)
    {
       case 1:cout<<"\nEnter The Number Of Members You Want To Add: ";//add
	      cin>>n;
	      first=new student;
	      cout<<"\nEnter Name: ";
	      gets(first->name);
	      cout<<"Enter Roll: ";
	      cin>>first->roll;
	      first->next=NULL;
	      last=first;
	      for(i=1; i<n; i++)
	      {
		x=new student;
		cout<<"\nEnter Name: ";
		gets(first->name);
		cout<<"Enter Roll: ";
		cin>>first->roll;
		x->next=NULL;
		last->next=x;
		last=x;
	      }
	      break;
 
       case 3:do//delete
	      {
		if(first!=NULL)
		{
		  cout<<"\nEnter The Roll: ";
		  cin>>val;
		  delet(first, val);
		  display(first);
		}
		else
		{
		  cout<<"\nLIST EMPTY!!!";
		  getch();
		  break;
		}
		cout<<"\n\nDo you want to continue (y/n)?\n";
		cin>>ch;
	      }while(ch=='y'||ch=='Y');
	      break;
 
       case 4:if (first!=NULL)//display
	      {
		display(first);
	      }
	      else
	      {
		cout<<"\nLIST EMPTY!!!";
	      }
                      getch();
	      break;
 
     **exit and default**
    }
  }
}

#include <sstream>
#include <iostream>
using namespace std;
 
int main() {
  string s;
  int i;
 
  cout << "Please enter an integer> ";
  getline( cin, s );
 
  if (!(stringstream( s ) >> i))
    cout << "That wasn't an integer!\n";
  else
    cout << "Thank you\n";
 
  return EXIT_SUCCESS;
  }

void delet(student*first, int val)
{
  student*ptr,*list,*back;
  if(first->roll==val)
  {
    ptr=first;
    first=first->next;
    delete ptr;
  }
  back=first;
  ptr=ptr->next;
  while(ptr!=NULL)
  {
    if(ptr->roll==val)
    {
      list=ptr;
      back->next=ptr->next;      
      delete list;
     }
     back=ptr;
     ptr=ptr->next;
  }
}